Tyrrell Hatton held his nerve to close out a maiden PGA Tour triumph at the Arnold Palmer Invitational by a single stroke.

Englishman Hatton went into Sunday with a two-shot lead but was taken to the wire by Marc Leishman amid unforgiving conditions at Bay Hill, where there was only one round in the 60s over the course of the weekend.

Rory McIlroy was one of the stars to suffer, as a run of five over in the space of five holes effectively ended his challenge before finishing tied for fifth with a four-over 76.

Hatton opened with a bogey but reached the turn three ahead thanks to back-to-back birdies.

He found water at 11, where a double bogey put his bid for glory back in the balance and he headed to the last one ahead of Australia's Leishman.

It was an advantage the 28-year-old managed to retain, carding 74 to finish four under for the tournament.

"It's hard to explain. It's just an incredible feeling," Hatton told the Golf Channel after his win.

"It was such a tough day today, actually felt like I was kind of playing myself out of it a little bit when I made double on 11. When I saw the scoreboard on I think it was the 14th green I realised I had I think it was a one- or two-shot lead at the time and I was a little bit surprised.

"But to hold on and win here at such an iconic venue, I'm just over the moon."

South Korea's Im Sung-jae finished third at two under, with Bryson DeChambeau fourth on one under overall.